Ventilation crossmembers are to be found in motor vehicles, in particular as elements of dashboard panel crossmembers.
In addition to their functions concerning the rigidity of the vehicle, they are used for conveying a flow of air coming from the air conditioner or the heater to vents that are disposed in the dashboard panel. They thus include a duct of insulating material for conveying this flow of air to the cabin, while preserving its temperature properties.
The crossmember is made of metal. Passing air directly along the metal tube gives rise to large amounts of heat being lost from the air being conveyed. It is therefore necessary to line the metal crossmember with a material that is not as good a conductor as metal. Ventilation crossmembers generally include a ventilation duct of plastics material placed inside the metal crossmember.
There are numerous techniques by which a ventilation crossmember with a plastics material duct can be made.
In a first technique, the inside duct is overmolded within the tubular metal crossmember out of plastics material. That technique is complex to develop.
In a second technique, the plastic duct is inserted into the channel.
In a first variant, the duct is inserted into the channel during fabrication thereof, e.g. while it is being made from two metal half-shells that are fitted one to the other. Under such circumstances, the duct presents an emerging portion that conventionally provides the connection with the vent.
In a second variant, the metal beam is fabricated initially and presents, at least in part, a tubular zone. Under such circumstances, the duct is introduced into the crossmember by being slid along the tubular channel, and as a result it does not present any emerging portion.
In a third variant, the ventilation crossmember is fabricated by folding a metal sheet so that the section of the crossmember forms a 6-shape or an 8-shape. The closed zone, or one of the closed zones with an 8-shape, forms a channel into which the plastics material duct is introduced by sliding.
Furthermore, the top portion of the 6-shaped section member is also considered as being a tubular zone even if it is not completely closed, and it may also contain a duct of insulating material for channeling of a flow of gas.
At the location provided for a vent, an opening is made in the channel and also in the duct.
Nevertheless, in the two last-described variant fabrication techniques, the opening of the duct lies inside the channel. Consequently, there arises the problem of connecting the duct to the vent while complying with overall ventilation constraints.
The object of the invention is thus to solve this problem.